Multicompartment package with internal breaker strip



E. W. BOLLMEIER ETAL Filed March 5, 1956 ,477D /VE 5 MULTICOMPARTMENTPACKAGE WITH INTERNAL BREAKER STRIP April 12, 1960 u mm wm Wwf Y m mur 25 m wm M 6 ...m fm /f H w WF f f Wn@ m f X /w ,/N 6 I i HH -l WMULHCOMPARTMENT PACKAGE WITH INTERNAL BREAKER srRn Emil Wayne Bollmeier,Mendota Heights, and- Leo F.

Vokaty, New Canada Township, Ramsey County,

Minn., assignors to Minnesota Mining & Manufacturlng Company, St. Paul,Minn., a corporation of Delaware Y Application March s, 1956, serial No.569,538 i Claims. (Cl. 20G-47) This invention relates to the packagingof liquid or plastic materials, and particularly to interreactivematerials which, when mixed together, set up or cure to aheat-resistant, hard and tough state. The invention relates to thepackaged products and in particular to the novel multicompartmentpackage having an internal breaker stripv providing for removal at willof the bar rier between separate compartments of the package.

Various liquid or plastic components may be enclosed in the separatecompartments of the package. Upon breaking of the interior barrier orbarriers, Ithese components may then be eiectively mixed together byhand manipulation of the outer envelope of the package. While the;contents need not be reactive with each other, they maybe, andpreferably are, interreactive either at room temperature or on theapplication of heat. A typical andvprefen'ed combination of reactivecomponents comprises as a iirst material a liquid epoxy 4resin and as asecond material a stable mixture of liquidV organic polysulde polymerand a tertiary amine activator for the epoxy resin. When mixed together,these two materials react exothermally and produce a heat-resistant,hard and tough resinous product which is particularly useful as an'electrical insulating material.

The invention will now be more fully described in connection with theaccompanying drawing, in which:

.Figure 1 is a planview, and Figure 2 is a cross-sectional view, of apreferred form of our multicompartrnent package. 'FiguresS' and 4illustrate, in cross-section, modiied forms of internal barriers inthepackage of Figures 1 andy 2;

Figure 5 is a sectional View of an alternative type of multicompartmentpackage;l n 'i Figures 6, 7 and 8 illustrate inAcross-section additionalmodifications of internal barriers; and

Figure 9 is a plan view of common edge portions of two `of the packagesof Figure 1 during a typical conv tinuous process of manufacture.

The package 10 of Figures 1 and 2 is made of two sections 11 and 12 ofthermoplastic polymeric film, heat sealed at the edges 13 to provide ahermetically closed envelope,v The two sides of the package are alsoheat sealed to the opposite surfaces of an interiorV breaker strip 15Y.along a central area 14, thus separating the package 10 into `twocompartments, oneof whichcontains, for example, a liquid epoxy resin,the other then containing curing agents and activators for the epoxyresin. The seal at the breaker strip is of sufficient strength tomaintain complete separation of the reactive contents of the twosegments of the envelope during all normal handling,l packaging,shipping and storing operations.`

TheY heat seal between the sections 11 and12 of thermo# plastic lm andthe breakeristrip 15 is conveniently made-by a process involving passingone of thetwo sheet materials in strip form continuously over a rollerhaving a narrow peripheral `heated area, passing the 2,932,385 PatentedApr. 12, 1(9 60 Y from the second of the partially heated rollers. Sucha process is capable of providing a bond between the several surfaceswhich is fully as strong as the bond produced between the two identicalouter sheet materials under heat and pressure, but only if the breakerstrip is also identical in physical structure with Ithe outer sheets. Inthe present instance, the breaker strip being of dissimilar` physicalstructure is, surprisingly, found to adhere with considerably reducedforce to the outer sheets. The continuous strip formed as aboveindicated is -then formed into separate two-compartment packages bysealing under heat and pressure the edges 13 as indicated in Figure 1and separating the packages along the connecting edge seal. The liquidor plastic reactive materials are metered into the compartments thusprovided just prior to completion of the peripheral seal.

In activating and using the package of reactive resinforming componentsjust described, the two panels 11 and 12 are separately gripped at thecentral areas of one of the compartments and are jerked rapidly apartalong the central seam 14, thus 4breaking the seal between ione or theother of the panels and the breaker strip 15 without damaging thepermanent edge seal 13, and permitting the reactive contents to becombined within the envelope. Combination is effected by handmanipulation of the envelope and is continued until a homogeneousmixtureis obtained and the reaction has commenced'. One corner of the envelopeis then opened, for example by cutting along dotted line A of Figure 1,and the contents flow or are squeezed out into a waiting mold or othercavity as desired, where the reaction continues to completion.

From the application described, it will be apparent that the heat sealbetween the panels 11 and 12 and the breaker strip 15 must besubstantially less strong than the heat seal between the panelsthemselves at the outer peripheral edge 13.

l It has been found that any attempt to produce a differential heat sealby pressing the two panels directly together at temperatures orpressures lower than those required to provide the rupture resistantedge seal 13, invariably results either in la strong seal which cannotreadily be broken or in a weakseal which is incapable of maintaining thedesired separation between the two compartments of the envelope. Evanthough accurate control of temperature, pressure and time be achieved,the normal variations in thickness of extruded iilm, surfaceirregularities, .and other uncontrollable variations precludey thevrformation of such internal seals on any commercially useful basis.

We have now found that the insertion of a suitable breaker strip 15between the tilm sections 11 and 12 overcomesthese difficulties andprovides a package which is entirely resistant to accidental joining ofthe several compartments, while being easily activated by hand pullingwhenever desired. Surprisingly, we have found thatfthe breaker strip maybe identical in chemical composition with the outer iilms 11 and 12, theonly necessary diference being a dierence in physical orientation orequivalent property.

As a preferred example, the envelope of Figures l and 2 is produced frompolyethylene lm which has been produced by extrusion from a tubing die,and the barrier strip 15 is produced from a film of chemically identicalpolyethylene Vwhich has been extruded from a flat sheeting die, and toapproximately the same thickness. The ma- 3 terials appear to weldtogether under heat and pressure to substantially the same degree, butit is found that the bond obtained between the two dissimilar films,while being entirely adequate to maintain separationl between the twocompartments of the package during normal handling, is still readilybroken by hand jerking or pulling on the two film walls of the envelopeadjacent the center seal. kOn the other hand, the edge bond 13 is foundto be completely resistant to such hand pulling, the film ordinarilybreaking at some point removed from such bond when placed undersuflicient stress.

Polyethylene film alone is somewhat lower in tensile strength than maybe required for certain types of packages. The lm is desirablyreinforced by laminating with another film, such as cellophane orpolyester lm, or metal foil, or paper, which has much higher tensilestrength, but is incapable of heat sealing. In such structure; thepolyethylene surface of the composite film forms the inner surface ofthe envelope and the product is therefore identiiiable as athermoplastic polymer film. IThe breaker strip is not laminated, but iscomposed entirely of polyethylene having a different physicalorientation from that of the polyethylene layers of the films 11 and 12forming the container.

The same results are obtained by reversing the two types of films, i.e.,by employing for the envelope a lm which has been prepared by extrusionfrom a flat sheeting die, and for the breaker strip a film formed with atubing die.

Equivalent results are obtained with envxelopes and breaker strips whichare chemically different while still capable of forming an effectiveheat seal having less resistance to rupture than a heat seal of eithermaterial to itself. One example is an ethylcellulose-envelope with abreaker strip of plasticized nitrocellulose. Another is apolyethylene-lined envelope with a chlorinated rubber breaker strip. e

While the bond between the film and the barrier strip of the package ofFigures 1 and 2 will ordinarily break along the plane of the initialjuncture between the two, there may be at times some transfer of polymerfrom the breaker strip to the outer iilrn, or vice versa, when thepackage is activated. The modified structures illustrated in Figures. 3and 4 provide for deliberate transfer of portions of the breaker stripto the outer films.

In Figure 3, the two films 31 and 32, corresponding with iilms 11 and 12of Figure 2, are bonded to opposite sides of breaker strip 35 whichconsists of a central fibrous portion 33 and surface lms 36 and 37.Thesurface films are of the same composition as the envelope, and formwith the. latter a heat seal which is equally as strong as the sealformed around the outer edges S13-of the envelope 10 of Figures. 1 and2. The fibrous central layer 38 is suiciently strong to provide adequateresistance to ordinary handling, and is suiiiciently dense to preventany appreciable transfer of liquid from one compartment of the packageto the other. However thersection 38 provides a weakened plane at thecenter of the breaker strip, so that, when the sides of the package arejerked apart, the breaker strip splits along this central plane. Theresulting two halves of the breaker strip remain attached to therespective sides of the envelope. YMixingrof the liquid or plasticcomponents is then accomplished by hand manipulation as in the case ofthe envelope in Figures 1 and 2.

An example of a structure corresponding to that illustrated in Figure 3employs as the breaker strip a Structure consisting of a thin porouspaper coated on both surfaces with a thin continuous llayer ofpolyethylene which is heat scalable to' the polyethylene-lined outerenvelope. The paper center remains'porous, any slight penetration by thereactive materials in the package resulting in the formation of animpervious resinous reaction prod- .uct` along one or the other of itsexposed-edges.

f aeaasse Y breaker strip 45 a strip of polymeric material which issubstantially softer and of lesser internal strength than thethermoplastic interior surface portion of the films 41 and 42 of theouter envelope, to which it is heat sealed. Activation of the packagebyierking apart the side walls 41 and 42 then results in a tearing awayof a substantial portion of the breaker strip 45, as indicated by thedotted lines 46, the material remaining attached to one or the other ofthe envelope walls. Materials which have proven highly satisfactory insuch a structure include high molecular weight polyethylene iilmenvelopes and low molecular weight, but still solid, polyethylenebreaker strips.

The structure'. illustrated in Figure 4 employs as the 75 The envelopestructures thus far illustrated have been indicated as constructed oftwo separate sections of lm, sealed around the entire periphery as wellas along the central area 14. The same results may be obtained byemploying a single section of film, folding it along a centrol' line toform an edge, and then completing the envelope by heat sealing theremaining portions as necessary. A still further variation employsextruded tubular lm as the envelope, the breaker strip being insertedand sealed in place across a centralsection and the ends of the tubethen being closed by heat sealing. The liquid or plastic contents areobviously introduced into their respective compartments prior to nalheat sealing, and may be introduced either at the end or at a side ofthe package, depending on the particular structure employed as well asother factors.

A somewhat different but closely analogous structure is illustrated inFigure 5. `In this example, the package 50 consists of arelatively'rigid but still flexible one-piece envelope 51 having aninternal peripheral channel 59 into which is set a closely iitting andsomewhat less flexible diaphragm 55 serving as a breaker strip. Thepackage is activated by pressure applied to one end of the package orcapsule, causing the diaphragm to be snapped out of its normal retainingchannel, thus permitting mixing of the interreactive contents. Thereactive mixture is then forced from the capsule through the tip 52which is opened for this purpose by cutting along dotted line A.

The breaker strip or diaphragm 55 of Figure 5 is not required to be heatsealed to the walls 51 of theV capsule 50, but the relative rigidity ofthe structure, as compared withl the structures illustrated in theprevious figures, produces substantially the equivalent effect. Theliquid or plastic contents are prevented from intermingling prior toactivation of the cartridge. Ihe breaker strip is effectively removedfrom its initial position by manipulation of the envelope when required,and by stresses which are' insufficient to cause damage to the outerenvelope.

The breaker strip 65 of Figure 6 is formed of two layers66 'and 67 ofthermoplastic film material of the same chemical but different physicalstructure. The two sections are lightly bonded together, e.g., bytechniques. herein describedand the composite is bonded to the two outeriilms `61 and 62 forming the center seal ofthe package as'shown inFigure 1. When the package is opened, the breaker strip fails along thecentral interface, thus permitting the reactive contents of the twocompartments of the package to be intermixed.

'Ihe packages of which the breaker strip and' adjacent portions areindicated in Figures 7 and 8 provide for the inclusion of a thirdreactive component within the breaker strip itself. In Figure 7, thebreaker strip is in the form of a hollow thin sealed tube or cylinder,sealed along opposite paraxial areas to the outer films 71 and 72. Inthis case the latter films are indicated as of composite structure,having an inner thermoplastic layer and an outer layer of increasedstrength. Such a film has already been described in connection with thedescriptionof' the package in Figure 1. The thin film formingV thebreaker strip 75 has sufficient thickness or body to permit theformation of a strong bond between it' andi the thermoplastic surfacesof the outer films', but isl much lower inftensile strengththanthelaminated films. When the latter are jerked apart, in using the package,the lm of the breaker stripV fails, thus liberating the reactivecomponent initially contained` therein Y and also permitting mixing ofthe `reactive components of this and the other two chambers of thepackage.V

Another modification, illustrated in Figure 8, employs a tubular breakerstrip 8S constructed of two strips 86 and 87 of -thin thermoplasticfilmmaterial sealed to the'outer laminated Vlms 81 and 82 and to eachother along the edges, but separated along the central areas to form athird compartment for reactive material. It will be apparent that thefilms 86 and 87 may be sealed to the outer sheets 81 and 82 along areasother than the sealed edge areas of the breaker strip `85. Since thefilms 86 and'87 are thinner and of lower tensile strength than the outerlaminates, the breaker strip fails in the same manner as that of Figure7, i.e., by tearing of the film material, and hence the several bondsbetween thermoplastic surfaces may be made as strong as desired. I

In all of these packages, it will be observed that the binder `stripprovides an increased thickness at the outer edge of the package, i.e.,at the corner 19 of Figure 1. Undersuch conditions it would normally beexpected thatleakage would occur at such points due to insuicientbonding at the 'juncture between the breaker strip and the outer sheetmaterials. Surprisingly, the packages of this invention are found to becompletely free of any such leakage, even after the package has beenactivated by jerking the outer panels rapidly apart along the centralseam as hereinbefore described. It is believed that this result isaccomplished in 4the following manner. As shown in Figure 9, theformation of a seal between the outer sheet materials to forma commonedge of adjacent packages in a continuous strip of the film materialresults in a displacement of the thermoplastic polymer at the cornerarea 19, as indicated by the extension of the dotted line indicating theboundaries of the breaker strip 15. In the packages of Figures l and 2,4, 6, 7 and 8, the thermoplastic breaker strip is effectively masticated`and integrated with the thermoplastic material of the outer film orlaminate. In the structure of Figure 3, the thermoplastic materialadditionally penetrates and impregnates the fibrous layer 38. In allcases, there is produced a peripheral bond 13 which is no thicker at thecorner area 19 than at any other point around the entire periphery ofthe package. The corner area is at least as well bonded as the remainderof the peripheral seal, and in many cases is found to have `a superiorbond due to the additional sligh-t ridge of polymer along the inner edgeof the peripheral seal, as at area a of Figure 9. As before indicated,cutting the seal along the central line c of Figure 9 severs thecompleted package from the adjacent package next in line in thecontinuous method of manufacture described.

This application is a continuation-in-part of the copending applicationSerial No. 386,992 of Emil Wayne Bollmeier and Leo F. Vokaty, ledOctober 19, 1953.

What is claimed is as follows: l

1. A package comprising a hermetically closed envelope of thermoplasticpolymer lfilm enclosing a hollow breaker strip of a thermoplasticpolymer material having less internal strength than said lm, adherentlyheat sealed to said lm along a narrow line around the entire interiorcross-section of said envelope, and itself providing a hermeticallyclosed envelope interiorly of said package.

2. A multicompartment package comprising a hermeti- 6 under aV stressinsuicient to break th'e adherent bond between 'the envelope and thesurfaces of the breaker strip.`

3. The multicompartment package of claim 2 containing in one compartmenta liquid resinous component and in another compartment, separated fromsaid one compartmentY by lthe separable breaker strip,. another reactantmaterial reactive with said liquid resinous material to produce `aheat-resistant, hard and tough resinous product. Y.

4. A multi-compartment package for a plurality of separatelycompartmentized inter-reactive miscible contents, comprising Van upperthermoplastic polymer film wall section, a coinciding lowerthermoplastic polymer film wall section, and an intermediate narrowlaminar breaker strip across the entire width of said wall sections andintermediate the ends thereof, said breaker strip being sealed along itsentire length to corresponding opposing narrow areas of said wallsections to provide a disruptable barrier between the resulting twocompartments of said barrier, and said breaker strip comprising acentral disruptable porous fibrous layer having a thermoplastic polymerlm layer on each side thereof.

5. vA multi-compartment packageV as dened in claim 4 in which theopposing lateral edgev areas of said coinciding Wall sections arepermanently sealed together to form outer edges of said package, thefibrous layer of said breaker strip remaining internally substantiallyfree of the thermoplastic polymer film material between said sealed edgeareas and being impregnated with said material within said edge areas.

6. A multi-compartment package for a plurality of separatelycompartmentized inter-reactive miscible contents, comprising a firstthin flexible wall section having an inner exposed-surface thermoplasticpolymer film and a reinforcing film laminated thereto, a coincidingsecond thin texible wall section having an inner exposedsurfacethermoplastic polymer film and a reinforcing film laminated thereto,said inner' films being capable of being permanently sealed togetherunder heat and pressure, and an intermediate narrow breaker strip acrossthe entire width of said wall sections and intermediate the ends thereofand comprising a central thin fibrous layer having an exposed thinthermoplastic polymer film layer on each side thereof, welded alongopposite central flat surface areas of said strip to each of said wallsections along the full width of the inner surface of each said wallsection.

7. A multi-compartment mixing-package for a plurality of separatelycompartmentized miscible contents, comprising a rst thin strong liexiblethermoplastic polymer film wall section, an opposing coinciding secondthin strong 'flexible thermoplastic polymer film wall section, saidsections being capable of being permanently sealed together under heatand pressure, and an intermediate narrow breaker strip across the entirewidth of said wall sections and intermediate the ends thereof,adherently heat sealed along opposite central -iiat surface areas ofsaid strip to each of said wall sections along the full width of theinner surface'of each said Wall section and providing acompartment-separating seal capable of being broken by hand pulling onsaid opposing wall sections.

8. A multi-compartment mixing-package for a plurality of separatelycompartmentized miscible contents, comprising a first thin flexible wallsection having an inner exposed-surface thermoplastic polymer film and areinforcing lm laminated thereto, a coinciding second thin flexible wallsection having an inner exposed-surface thermoplastic polymer film and areinforcing film laminated thereto, said inner films being capable ofbeing permanently sealed together under heat and pressure, and anintermediate narrow breaker strip across the entire width of said Wallsections and intermediate the ends thereof, adherently heat sealed alongopposite central at surface areas of said strip to each of said wallsections '7 along the full width of lthe inner surface .of :each saidwall section; said breaker striprcomprising a laminar web materialreadily separable into two laminae along Vlan interior plane andproviding a compartment-separating seal ycapable of being broken by handpulling on said opposing wall sections.

9. A multi-compartment mixing-package for a plurality of separatelycompartmentized mis'cible contents, comprising a :rst thin flexible Wallsection havingva'n inner exposed-surface thermoplastic polymer 4film anda reinforcing film laminated thereto, a coinciding second thin ilexiblewall section having an inner .exposed-surface thermoplastic polymer tilmand a reinforcing ilm laminated thereto, said inner lilms being capable.of rbeing permanently sealed together under heatand pressure, and anintermediate narrow breaker vstrip across .the `entire width of saidwall Vsections and intermediate .fthe ends thereof, adherently heatsealed alongop'osite central at surface areas of said strip to each ofsaid wall sections along vthe full width of the inner surface .ofeach'said wall section; said breaker strip being va strip 4ofthermoplastic polymer material having Vless internal strength than saidwall sections and providing a compartment-separating seal capable ofbeing brokenby hand'pulling on said opposing wall sections.

:10. A multi-compartment mixing-package for a plu; l

rality of separately compartmentized miscible contents, comprising a rstthin exible wall section having Van inner exposed-surface thermoplasticpolymer lrn and a reinforcing lilm laminated thereto, a coincidingsecond thin ilexible wall section having an inner exposed-surfacethermoplastic polymer lm and a reinforcing 'lm laminated thereto, saidinner films being capable of being permanently sealed together underheat and pressure, and an intermediate narrow breaker strip Vacross theentire width of said wall sections and intermediate the ends thereof,welded along opposite central flat surface areas of said strip to eachof said wall sections along'the ,full width of the inner surface of eachsaid wall sectionysaid breaker strip consisting of two layers ofthermoplastic ilm material lightly bonded together and providing acompartment-separating seal capable of being broken by hand pulling onsaid opposing wall sections.

References Cited in the le of this patent UNITED STATES PATENTS2,245,738 Taylor June 17, 1941 2,560,535 Allen Iuly17, 19,51

2,605,896 Rohdin Aug. 5, 1952 FOREIGN PATENTS 711,186 Great Britain June23. 1954

1. A PACKAGE COMPRISING A HERMETICALLY CLOSED ENVELOPE OF THERMOPLASTICPOLYMER FILM ENCLOSING A HOLLOW BREAKER STRIP OF A THERMOPLASTIC POLYMERMATERIAL HAVING LESS INTERNAL STRENGTH THAN SAID FILM ADHERENTLY HEATSEALED TO SAID FILM ALONG A NARROW LINE AROUND THE ENTIRE INTERIORCROSS-SECTION OF SAID ENVELOPE, AND ITSELF PROVIDING A HERMETICALLYCLOSED ENVELOPE INTERIORLY OF SAID PACKAGE.